1. Field of the Invention
The present invention relates to a process for the alkylation of organic aromatic compounds. More particularly the invention relates to a process for the co-production of cumene and secondary butyl benzene by concurrently alkylating benzene with propylene and butylene. More particularly the invention relates to a process for the concurrent co-production of cumene and secondary butyl benzene in a distillation column reactor where the unreacted benzene and olefin are concurrently separated from the products by fractional distillation.
2. Related Art
Cumene and secondary butyl benzene (SBB) are currently produced by the reaction of benzene and the respective olefin, i.e., propylene or butylene by acid catalysis. In some known processes the catalyst is highly corrosive and has a relatively short life, e.g., AlCl3, H3PO4 on clay, BF3 on alumina, and others require periodic regeneration, e.g., molecular sieves. The exothermicity of the reaction and the tendency to produce polysubstituted benzene require low benzene conversions per pass with large volume recycle in conventional processes.
U.S. Pat. Nos. 4,371,714 and 4,469,908 disclose straight pass alkylation of aromatic compounds using molecular sieve catalysts in fixed beds, however, both references disclose coking of the catalyst as a problem which necessitates frequently shutting down the unit and regeneration of the catalyst. U.S. Pat. Nos. 4,316,997 and 4,423,254 both disclose the use of acidic resins in fixed beds for the alkylation of aromatic compounds. Coking is also a problem with these catalysts.
U.S. Pat. No. 5,243,115 discloses a process for the alkylation of benzene with a C2 to C20 olefin in a distillation column reactor containing a fixed bed acidic catalyst in the form of a distillation structure.